The invention relates to a plunger for feeding and withdrawing an electronic component, in particular ICs, to and/or from a contact device that is connected to a test device, comprising a plunger retaining part and a plunger sliding part.
Electronic components such as, for example, integrated circuits (semiconductor components with integrated circuits) are usually checked for their functionality before they are mounted, for example, on printed circuit boards or used in some other way. The components to be tested are usually brought in contact with contact devices by an automatic handling machine usually designated as a “handler”, these contact devices being embodied in particular as contact sockets and being in electrical contact with a test head of a test device. After the end of the testing process, the components are removed from the contact devices again by the handler and are sorted depending on the test result.
For retaining and contacting the components, handlers usually have plungers, i.e. longitudinally displaceable retaining units which can be reciprocated in the manner of a piston, which can hold the components in particular by applying a suction force by negative pressure (vacuum). After placing the components on the plunger head, the plungers are brought into a position inside the handler in which they can be advanced on a rectilinear path further towards the contact devices until the components come in contact with the contact devices. After carrying out the test processes, the components are removed from the test head again by the plunger and positioned in such a manner that they can be removed from the handler via an unloading station and can be sorted depending on the test result.
The plunger head on which the component to be tested is held by suction force is usually detachably secured to the base body of the plunger sliding part by screws. As a result, when changing the component type, it is possible merely to replace the plunger head by another plunger head adapted to the new type of component whilst the remaining part of the plunger can remain unchanged. However, exchanging the plunger head is associated with a considerable amount of work and frequently cannot be accomplished in the desired simple manner.